Honda says to just coat with grease because the drive oil is supposed to circulate.
After you clean out all the crud, make sure the 2 holes at the bottom of the pinion cup are clear. (use a wire or blow air in briefly) One hole delivers the oil and the other drains it back to the final drive. If you tilt the drive cup-down, oil should start to come through the holes.
I coat the splines with grease (moly) and then also drizzle some drive oil in the cup and on the shaft to cup seal. It's important that this seals to promote circulation.
Shaft before cleaning (note the oil coating):

Pinion Cup during cleaning (keep those holes clear):
